阅读说明：本技术 补偿通过渐进片材成形而形成的结构的回弹的系统和方法 (System and method for compensating for springback of a structure formed by progressive sheet forming ) 是由 A·J·E·斯蒂芬 于 2021-05-31 设计创作，主要内容包括：本发明涉及补偿通过渐进片材成形而形成的结构的回弹的系统和方法,公开了渐进片材成形系统和方法,其被配置为通过渐进片材成形过程来形成结构。所述渐进片材成形系统和方法包括成形控制单元,所述成形控制单元补偿将通过所述渐进片材成形过程形成的结构的回弹。(Progressive sheet forming systems and methods are disclosed that are configured to form structures by a progressive sheet forming process. The progressive sheet forming system and method includes a forming control unit that compensates for spring back of a structure to be formed by the progressive sheet forming process.)

1. A progressive sheet forming system (100) configured to form a structure (110) by a progressive sheet forming process, the progressive sheet forming system (100) comprising:

a forming control unit (102) that compensates for springback of the structure (110) to be formed by the progressive sheet forming process by modifying at least a portion of a tool path (114) of a forming tool (108) used to form the structure (110) based on the springback.

2. The progressive sheet forming system (100) of claim 1 wherein the forming control unit (102) determines a target shape of the structure (110) to be formed and simulates a progressive sheet forming operation associated with the target shape.

3. The progressive sheet forming system (100) of claim 2, wherein the forming control unit (102) compares a difference between the target shape and a structure (110) resulting from the progressive sheet forming operation to determine one or more offsets (123) that compensate for the springback, wherein the one or more offsets (123) relate to force vectors that oppose the springback.

4. The progressive sheet forming system (100) of claim 2 wherein the forming control unit (102) virtually simulates the progressive sheet forming operation while the forming tool (108) does not physically operate on the structure (110).

5. The progressive sheet forming system (100) of any of claims 1 to 4, wherein the forming control unit (102) determines geometric errors (127) across the entire simulated structure (110).

6. The progressive sheet forming system (100) of claim 5 wherein the forming control unit (102) shifts (123) a point (322) on the contour (121) perpendicular to a target geometry in response to the geometric error (127) being greater than a predetermined threshold.

7. The progressive sheet forming system (100) of claim 6, wherein after the forming control unit (102) shifts (123) the points (322), the forming control unit (102) determines whether any set of consecutive contours (121) has a maximum vertical deviation (117) greater than a maximum step down (119).

8. The progressive sheet forming system (100) of claim 7 wherein, in response to the presence of at least one set of consecutive profiles (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119), the forming control unit (102) inserts at least one compensation profile (121) between a target profile (121) and at least one profile (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119).

9. A progressive sheet forming system configured to form a structure (110) by a progressive sheet forming process, the progressive sheet forming method comprising:

compensating, by a forming control unit (102), for springback of a structure (110) to be formed by the progressive sheet forming process, wherein the compensating comprises modifying at least a portion of a tool path (114) of a forming tool (108) used to form the structure (110) based on the springback.

10. The progressive sheet forming method of claim 9 wherein the compensating comprises:

determining a target shape of the structure (110) to be formed; and

simulating a progressive sheet forming operation associated with the target shape.

Technical Field

Embodiments of the present disclosure generally relate to systems and methods for compensating for spring back of structures formed by progressive sheet forming.

Background

Some structures are formed by progressive sheet forming. In particular, progressive sheet forming provides a method of forming thin structures from metal. Forming tools typically include a round, blunt operating head that is pushed or otherwise urged against the surface of the sheet metal suspended in a clamp, assembly fixture, or the like to provide an improved three-dimensional shape.

When forming the sheet metal article, a certain amount of strain in the sheet metal is elastically recovered, which is referred to as spring back. A known method of compensating for spring back with respect to the forming process on the die is to modify the shape of the tool in an iterative manner until a portion with sufficient geometric accuracy is produced. Such a process may be performed virtually by first simulating the process and then by comparing the simulation results to expected results. The mold may then be modified to reverse the offset.

However, elastic forward compensation (i.e., compensation for spring back) cannot generally be applied to progressive sheet forming because small changes in geometry can result in large changes in the topology of the tool path, which can have an unexpected effect on the final geometry of the formed part. For example, in progressive sheet forming, nubs may completely change the topology of the tool path, and individual islands of material may be formed in the resulting portion, which has a number of disadvantages. First, tool engagement and retraction can leave marks on the part. Second, the formation of islands of material may leave bumps in the sheet of material that may render it unusable or otherwise unacceptable. Third, the bumps may reorder which portions of the sheet are formed, which may affect workflow, such as by changing the way the sheet behaves during the forming process. Such changes may eventually invalidate any correction steps.

Disclosure of Invention

There is a need for a system and method for compensating for spring back in a progressive sheet forming process that forms a structure. That is, there is a need for a system and method for spring forward compensation during progressive sheet forming of a structure. Additionally, there is a need for systems and methods that maintain a tool path during the progressive sheet forming process while also compensating for spring back to form a desired structural shape.

In view of these needs, certain embodiments of the present disclosure provide a progressive sheet forming system configured to form a structure by a progressive sheet forming process. The progressive sheet forming system includes a forming control unit that compensates for spring back of a structure to be formed by the progressive sheet forming process. For example, the forming control unit compensates for the springback by modifying at least a portion of a tool path of a forming tool used to form the structure based on the springback.

In at least one embodiment, the forming control unit determines a target shape of a structure to be formed and simulates a progressive sheet forming operation in relation to the target shape. For example, the forming control unit compares the difference between the target shape and the structure resulting from the progressive sheet forming operation to determine one or more offsets that compensate for the springback. The one or more offsets relate to the force vector (i.e., the magnitude and direction of the force) opposing the rebound. The forming control unit may virtually simulate the progressive sheet forming operation, while the forming tool does not physically operate on the structure.

In at least one embodiment, the shaping control unit determines geometric errors across the simulated structure. The shaping control unit shifts a point on the contour perpendicular to the target geometry in response to the geometric error being greater than a predetermined threshold. After the shaping control unit offsets the points, the shaping control unit determines whether any set of consecutive contours has a maximum vertical deviation greater than a maximum step down. In response to there being at least one set of consecutive profiles having a maximum vertical deviation exceeding the maximum step down, the shaping control unit inserts at least one compensation profile between a target profile and at least one profile having a maximum vertical deviation exceeding the maximum step down. The shaping control unit also maps the compensation contour onto the structure to form a compensated geometric shape.

In at least one embodiment, the shaping control unit maps a contour with at least one surface of the structure.

In at least one embodiment, the progressive sheet forming further comprises the forming tool. The forming tool is configured to follow the modified tool path to form the structure.

Certain embodiments of the present disclosure provide a progressive sheet forming method configured to form a structure by a progressive sheet forming process. The progressive sheet forming method includes compensating for springback of a structure formed by the progressive sheet forming process by a forming control unit.

In at least one embodiment, the compensating comprises determining a target shape of the structure to be formed and simulating a progressive sheet forming operation associated with the target shape. The compensation further includes comparing a difference between the target shape and a structure resulting from the progressive sheet forming operation to determine one or more offsets that compensate for the spring back. The simulating may include virtually simulating the progressive sheet forming operation without the forming tool physically operating on the structure.

In at least one embodiment, the compensation includes determining geometric errors across the simulated structure. The compensating further includes offsetting a point on the contour perpendicular to the target geometry in response to the geometric error being greater than a predetermined threshold. The compensating further includes determining whether any set of consecutive contours has a maximum vertical deviation greater than a maximum step down after the shifting. The compensating further comprises, in response to there being at least one set of consecutive contours having a maximum vertical deviation exceeding the maximum step down, inserting at least one compensation contour between the target contour and at least one contour having a maximum vertical deviation exceeding the maximum step down. The compensating further includes mapping the compensation contour onto the structure to form a compensated geometry.

In at least one embodiment, the compensating comprises mapping the contour to at least one surface of the structure.

In at least one embodiment, the compensating comprises modifying at least a portion of a tool path of a forming tool used to form the structure based on the springback.

Drawings

Fig. 1 illustrates a schematic block diagram of a progressive sheet forming system according to an embodiment of the present disclosure.

FIG. 2 shows a flow diagram of a springback compensation algorithm for progressive sheet forming according to an embodiment of the present disclosure.

Fig. 3 shows a top view of a structure according to an embodiment of the present disclosure.

Fig. 4 shows a perspective side view of the structure of fig. 3.

Fig. 5 shows a perspective side view of a target surface according to an embodiment of the present disclosure.

FIG. 6 illustrates a perspective side view of a sheet offset surface above the target surface of FIG. 5, in accordance with an embodiment of the present disclosure.

FIG. 7 illustrates a perspective side view of a tool offset surface above the sheet offset surface of FIG. 6 above the target surface of FIG. 5, in accordance with an embodiment of the present disclosure.

FIG. 8 illustrates an internal perspective view of the tool offset surface above the sheeting offset surface, which is above the target surface.

Fig. 9 illustrates a perspective view of a tool offset surface having a tool path in accordance with an embodiment of the present disclosure.

FIG. 10 shows a side view of a set of consecutive profiles having a maximum vertical deviation greater than the maximum step down.

FIG. 11 shows a simplified diagram of a structure having an original tool path and a modified tool path.

Detailed Description

The foregoing summary, as well as the following detailed description of certain embodiments, will be better understood when read in conjunction with the appended drawings. As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not necessarily excluding plural of the elements or steps. Furthermore, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular condition may include additional elements not having that condition.

Certain embodiments of the present disclosure provide a progressive sheet forming system and method including a forming control unit configured to compensate for springback of a structure to be formed. In at least one embodiment, the shaping control unit maps the contour of the structure, rather than just mapping the surface and re-cutting the contour, thereby creating a non-Z horizontal path. In at least one embodiment, the forming control unit continuously inserts paths between pairs of undesired tool paths, such as by referencing a library of contours relative to the target (desired) shape and mapping all contours at each step, or by bearing at the original Z level around each path and generating new paths between pairs of undesired contours on the target shape.

Certain embodiments of the present disclosure provide systems and methods for correcting spring back during progressive sheet formation of a structure. The system and method include calculating geometric errors over the entire section, modifying the geometry based on the errors, mapping the original tool path onto the new geometry, and finally, inserting additional tool path contours if appropriate. In at least one embodiment, the tool path can be modified instead of regenerating the tool path at each iteration of compensation.

In at least one embodiment, embodiments of the present disclosure provide a system and method that corrects for errors associated between manufactured part shapes and designed target shapes due to springback of parts in progressive sheet forming. To reduce the errors, the forming control unit runs a simulation (or actual physical forming pass) to determine the appearance of the final product and to determine the geometric errors. If the error is unacceptable, the shaping control unit modifies the target geometry by pushing the target geometry in the opposite direction of the error, such that the shaping tool (e.g., a shaping stylus) pushes the target geometry in the opposite direction of the error. The original tool path is then mapped onto this new geometry. In at least one embodiment, additional contours may be inserted if the distance (such as height) between contours is too large after modifying the current set of contours.

In progressive sheet forming, the tool path is given by a discrete set or points which may be connected by straight lines. These points are located on a surface called the tool offset surface. Corresponding to these tool path points are contact points, which are where the forming tool contacts a portion geometry for a given contact point. These points are also located on a surface called the sheet deflection surface, which has a 1:1 correspondence with the tool deflection surface. To map the tool path, the same transformation as for the target geometry is applied to the contact points and vice versa. The compensation algorithm modifies the target geometry by offsetting (e.g., vertically). Because the sheet offset surface is defined by offsetting the target geometry, the sheet offset can be directly offset. Once this occurs, the forming control unit may recalculate the points on the tool offset surface that correspond to the contact points and connect these points by straight line segments to generate a complete tool path.

Fig. 1 illustrates a schematic block diagram of a progressive sheet forming system 100 in accordance with an embodiment of the present disclosure. The progressive sheet forming system 100 includes a forming control unit 102 in communication with a structure database 104, such as through one or more wired or wireless connections, and a user interface 106, such as through one or more wired or wireless connections. The shaping control unit 102 may be co-located with one or both of the structure database 104 and/or the user interface 106. Optionally, the forming control unit 102 may be located remotely from one or both of the structure database 104 and/or the user interface 106. In at least one embodiment, the forming tool 108 includes an operating member (such as a motor) controlled by a controller or control unit, which may be separate and distinct from the forming control unit 102.

The progressive sheet forming system 100 also includes a forming tool 108 configured to operate to form a structure 110. In at least one embodiment, the forming tool 108 is a forming stylus having a rounded, blunt operating end 112, the rounded, blunt operating end 112 being configured to apply a force into the structure 110 to form various features (such as curves, bends, dimples, etc.) therein and/or thereon. The forming tool 108 operates on the structure 110 over the tool path 114 to form the desired shape of the structure 110.

In at least one embodiment, the forming control unit 102 communicates with the forming tool 108, such as through one or more wired or wireless connections. The forming control unit 102 is configured to operate a forming tool 108 to form a desired shape of a structure 110, for example formed from sheet metal. Alternatively, the forming control unit 102 may not be in communication with the forming tool 108 or configured to operate the forming tool 108.

The structure database 104 stores various data. For example, structure database 104 stores target data 116, rebound data 118, and tool path data 120. The target data 116 includes information about the target or desired structure to be formed. For example, the target data 116 includes information about the size and shape of the structure 110 that is desired to be formed.

Springback data 118 includes information about the springback effect when a force is applied into structure 110. For example, when a force is applied into a portion of the structure 110, the elasticity of the structure 110 causes a responsive spring-back.

The tool path data 120 includes information about the path to be followed by the forming tool 108 to form the structure 110. Tool path data 120 may include information about a target or desired tool path and a compensated tool path, including modifications to offset the springback of structure 110. For example, the offset relates to a force vector (magnitude and direction) that opposes rebound (e.g., the force vector opposes (at least partially in magnitude and direction) a force vector of a rebound force).

The user interface 106 includes a display 122, such as a monitor, television, touch screen, or the like. For example, the user interface 106 and the forming control unit 102 may be part of a computer workstation. In at least one other embodiment, the form control unit 102 and the user interface 106 may be part of a handheld device, such as a smart tablet, smart phone, laptop computer, or the like.

In operation, the forming control unit 102 determines a target or desired shape of the structure 110. For example, the forming control unit 102 may retrieve target shape data from the target data 116. The forming control unit 102 then simulates a progressive sheet forming operation on a virtual representation of the initial structure (such as a sheet metal piece). For example, the forming control unit 102 may perform a virtual progressive sheet forming operation on the initial structure, while the forming tool 108 does not physically operate on the structure 110. In general, the forming control unit 102 determines a target shape of a structure to be formed and simulates a progressive sheet forming operation in relation to the target shape.

During the initial simulated forming operation, the forming control unit 102 operates on the initial structure on the tool path to form the resulting structure. The springback data 118 about the structure allows the forming control unit 102 to determine the springback effect during the forming process. The forming control unit 102 compares the resultant structure after springback with the target structure. The forming control unit 102 determines the difference between the target structure and the resulting structure. Then, the shaping control unit 102 offsets/cancels (offset) the difference between the target structure and the resulting structure to compensate for the springback. The forming control unit 102 compares the difference between the target shape and the structure resulting from the progressive sheet forming operation to determine one or more offsets that compensate for the spring back. In this way, the forming control unit 102 compensates for differences that occur due to springback to modify the forming parameters (such as the force applied into the structure). In this way, the forming control unit 102 determines a springback compensated forming plan, which includes the tool path and the forces exerted on the tool path, to be used by the forming tool 108 to form the structure 110 having the desired shape. The springback compensation shaping plan counteracts springback such that the structure 110 is formed to have a desired shape rather than an undesired shape due to the springback effect.

In at least one embodiment, during initial setup, the forming control unit 102 communicates with the structure database 104 to determine various aspects of the structure 110. For example, the target data 116 includes the desired part geometry (i.e., the desired size and shape), as well as the geometry of the forming tool 108.

The forming control unit 102 also determines a maximum step down, which is a predetermined maximum distance between tool path segments in the Z-direction. The maximum step down may be stored in the structure database 104 and/or in a memory of the shaping control unit 102 or a memory coupled to the shaping control unit. For example, the maximum step down may be 10 millimeters or less. In one example, the maximum step down is between 5 mm and 10 mm. Optionally, the maximum step down may be greater than 10 millimeters.

The forming control unit 102 also determines a target geometric tolerance, which is a predetermined tolerance with respect to the springback of the structure 110. The target geometric tolerance may be stored in the structure database 104 and/or in a memory of the forming control unit 102 or a memory coupled to the forming control unit. For example, the target geometric tolerance is a predetermined tolerance below which rebound compensation for deflection is not required. For example, the predetermined tolerance may be 0.05 millimeters or less. In such an example, if the resulting springback is less than 0.05 millimeters, the forming control unit 102 does not compensate for the springback. However, if the resulting springback exceeds the target geometric tolerance, the forming control unit 102 compensates for the springback.

In at least one embodiment, the method of compensating for spring back of a structure formed by progressive sheet forming begins with the forming control unit 102 simulating a progressive sheet forming process on the structure. For example, the forming control unit 102 virtually performs a simulated progressive sheet forming process, while the forming tool 108 does not physically operate on the structure 110. During the simulated progressive sheet forming process, the forming control unit 102 operates a virtual forming tool on the simulated structure using standard tool paths, such as may be stored in the structure database 104. During such operation, the forming control unit 102 determines the spring back effect on the simulated structure. In at least one embodiment, instead of virtual simulation, the forming control unit 102 may operate the forming control unit 102 on a test structure. In this way, simulated progressive sheet forming can be relative to a virtual forming tool and simulated structure, and/or relative to a forming tool 108 and test structure (such as a test version of the structure 110).

The shaping control unit 102 then determines the geometric error of the entire simulated structure. Geometric errors are the differences between the structures desired to be formed and the resulting structures caused by spring back of the operation during the simulation. For example, the geometric error is related to the difference (such as in size, height, etc.) in the corresponding profile between the structure desired to be formed and the structure exhibiting spring-back. If the resulting geometric error is acceptable (such as within a target geometric tolerance), the forming control unit accepts the result and the forming tool 108 may then operate on the structure 110 according to the simulated progressive sheet forming process.

However, if the geometric error is unacceptable (such as exceeding a target geometric tolerance), the forming control unit 102 offsets points on the contours (e.g., all contours) that are perpendicular to the target geometric shape as part of the local geometric error. Then, for the current profile set (i.e., the profile set of the resulting structure), the shaping control unit 102 determines whether any set of consecutive profiles 115 has a maximum vertical deviation 117 greater than a maximum step-down 119 (as shown in fig. 10). If there is no set of consecutive profiles with a maximum vertical deviation greater than the maximum step down, the forming control unit 102 returns to simulating a progressive sheet forming process.

However, if there is at least one set of consecutive profiles having a maximum vertical deviation exceeding the maximum step down, the shaping control unit 102 may then insert a compensation profile 121 (as shown in fig. 10) between the target profile (i.e., the desired profile) and the profile 115 having the maximum vertical deviation 117 exceeding the maximum step down 119. The shaping control unit 102 then maps the compensation profile onto the structure to form a new compensation geometry. The shaping control unit 102 then continues to perform such operations iteratively until all surfaces have been analyzed.

In at least one embodiment, the surface is modified first, and the contact points are accompanied by the modification. From the modified contact points, the tool offset point may be recalculated. In this way, the tool path can be mapped onto the new geometry.

As shown in the simplified example of fig. 10, one or more offsets 123 compensate for the spring back effect. Geometric errors 127 in the simulated structure may be caused by spring back.

As described herein, embodiments of the present disclosure provide a forming control unit 102 configured to compensate for spring-back associated with a progressive sheet forming process of a forming structure. The form control unit 102 not only maps the surface and re-cuts the contour. In at least one embodiment, the shaping control unit 102 maps the contour with the surface of the structure 110, thereby creating a non-z-horizontal path. In at least one embodiment, the forming control unit 102 inserts paths (such as iteratively and/or cumulatively) between pairs of undesired tool paths.

In at least one embodiment, the shaping control unit 102 modifies the tool path 114 to compensate for springback at each iteration of compensation, rather than regeneration. For example, the forming control unit 102 modifies at least a portion of the tool path 114 of the forming tool 108 for forming the structure 110 based on the springback. In at least one embodiment, when the geometric error is not large, the shaping control unit 102 can maintain a small perturbation in the tool path instead of generating a new topology in the tool path. By way of example, fig. 11 shows a simplified diagram of a structure 110 having an original tool path 114a and a modified tool path 114 b.

FIG. 2 shows a flow diagram of a springback compensation algorithm for progressive sheet forming according to an embodiment of the present disclosure. Fig. 2 illustrates a progressive sheet forming method. In at least one embodiment, the forming control unit 102 shown in fig. 1 operates based on the flow chart shown and described with respect to fig. 2.

At 200, the method begins by structurally simulating a progressive sheet forming process. The simulation may be virtual or on a test structure. At 202, geometric errors are determined over the entire simulated structure.

If at 204, the resulting geometric error is acceptable, such as less than a predetermined threshold (such as within a target geometric tolerance), the result is accepted at 205 (and the process ends at 218), and then the forming tool 108 may operate on the structure 110 according to the simulated progressive sheet forming process.

However, if at 204, the geometric error is not acceptable, such as greater than a predetermined threshold, then at 206, the tool contact point (e.g., profile) that is perpendicular (e.g., perpendicular to the current geometry or perpendicular to the original geometry) is shifted in a direction opposite the geometric error. Then, at 208, the maximum distance (e.g., z-bias) between each pair of consecutive profiles associated with the maximum pressure drop is calculated. At 210, it is determined whether any of the pairs have a deviation that exceeds a threshold (i.e., a maximum step down). If at 210 there is no set of consecutive contours with a maximum vertical deviation greater than the maximum step down, then the method proceeds from 210 to 211, where the tool position is recalculated for each contact point, while maintaining the order and orientation. The method then returns to 200. Optionally, instead of a maximum step down, embodiments of the present disclosure may utilize a maximum step of the tool path.

However, if at 210 there is at least one set of consecutive contours with a maximum vertical deviation that exceeds the maximum step down, then at 212, another contour is inserted between the target contour (i.e., the desired contour) and the contour with the maximum vertical deviation that exceeds the maximum step down. At 214, the compensated contour is then mapped onto the structure to form a new compensated geometry, and the method returns to 208. The process continues until all surfaces of the structure have been analyzed.

Optionally, in at least one embodiment, the process can be performed with respect to a mold. Likewise, the mold may also be modified to account for variations in the geometry of the structure being formed.

As used herein, the terms "control unit," "central processing unit," "CPU," "computer," and the like may include any processor-based or microprocessor-based system, including systems that use: microcontrollers, Reduced Instruction Set Computers (RISC), application specific integrated circuits, logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. This is exemplary only, and thus is not intended to limit the definition and/or meaning of such terms in any way. For example, the shaping control unit 102 may be or include one or more processors configured to control the operations thereof, as described herein.

The shaping control unit 102 is configured to execute sets of instructions stored in one or more data storage units or elements (such as one or more memories) in order to process data. For example, the control unit 102 may include or be coupled to one or more memories. The data storage unit may also store data or other information as desired or needed. The data storage elements may be in the form of physical memory elements within the information source or processor. The one or more data storage units or elements may include volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. By way of example, non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable PROM (EEPROM), and/or flash memory, and volatile memory can include Random Access Memory (RAM), which can be used as external cache memory. The data storage devices of the disclosed systems and methods are intended to comprise, without being limited to, these and any other suitable types of memory.

The set of instructions may include various commands that instruct the forming control unit 102 as a processing machine to perform specific operations, such as the methods and processes of the various embodiments of the subject matter described herein. The set of instructions may be in the form of a software program. The software may be in various forms (such as system software or application software). Additionally, the software may be in the form of a collection of separate programs, a subset of programs within a larger program, or a portion of a program. The software may also include modular programming in the form of object-oriented programming. The processing of input data by a processing machine may be in response to a user command, or in response to the results of a previous process, or in response to a request made by another processing machine.

The illustrations of the embodiments herein may show one or more control or processing units, such as a forming control unit 102. It should be understood that the processing or control unit may represent circuitry, or portions thereof, which may be implemented as hardware with associated instructions (e.g., software stored on a tangible and non-transitory computer readable storage medium such as a computer hard drive, ROM, RAM, etc.) to perform the operations described herein. The hardware may include state machine circuitry that is hardwired to perform the functions described herein. Optionally, the hardware may include electronic circuitry that includes and/or is connected to one or more logic-based devices, such as microprocessors, processors, controllers, and the like. Optionally, the shaping control unit 102 may represent processing circuitry, such as one or more of a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), microprocessor(s), or the like. The circuitry in various embodiments may be configured to execute one or more algorithms to perform the functions described herein. One or more algorithms may comprise aspects of the embodiments disclosed herein, whether or not explicitly identified in a flowchart or a method.

As used herein, the terms "software" and "firmware" are interchangeable, and include any computer program stored in a data storage unit (e.g., one or more memories) for execution by a computer, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (nvram) memory. The above data storage unit types are exemplary only, and are thus not limited to the types of memory usable for storage of a computer program.

Fig. 3 illustrates a top view of a structure 110 according to an embodiment of the present disclosure. Fig. 4 shows a perspective side view of structure 110. Referring to fig. 3 and 4, tool path 114 is superimposed onto structure 110. The tool path 114 is the path that the forming tool 108 follows as it forms the structure 110.

Referring to fig. 1, 3 and 4, the forming control unit 102 determines the tool path 114 of the structure 110 as needed (i.e., forming as needed). In at least one embodiment, the forming control unit 102 modifies the tool path 114 based on the determined springback, as determined during the simulated progressive sheet forming process. Fig. 11 shows a simplified example of an original tool path 114a and a modified tool path 114 b. In at least one embodiment, the tool path 114 used to compensate for spring back is substantially the same as the tool path before the simulated progressive sheet forming process. In this manner, the forming control unit 102 does not substantially alter the tool path 114, which may otherwise result in undesirable islands on the structure 110.

In at least one embodiment, the forming control unit 102 may first map the tool path onto a modified or target shape 110' (i.e., a shape modified to counteract the effects of springback). Typically, in progressive sheet forming, the tool path is determined by offsetting the target geometry by an amount specified by the sheet thickness, tool shape, tool size, etc. to generate the surface.

Fig. 5 illustrates a perspective side view of a target surface 300 according to an embodiment of the present disclosure. The target surface 300 is a surface corresponding to the desired size and shape of the target structure (i.e., the structure to be formed as desired). The forming control unit 102 (shown in fig. 1) determines a target surface 300, such as stored in the structure database 104.

FIG. 6 illustrates a perspective side view of a sheet offset surface 302 on a target surface 300 in accordance with an embodiment of the present disclosure. The sheet offset surface 302 is separate and distinct from the target surface 300 and is generally offset from the target surface 300 by a predetermined spacing 304, such as the thickness of the structure 110 (shown in fig. 3 and 4). For example, a spacing 304 between corresponding vertical points (e.g., corresponding vertical points 301 and 303) between target surface 300 and sheet offset surface 302 is the thickness of structure 110. The form control unit 102 (shown in fig. 1) determines a sheet offset surface 302, such as by configuring the surface to be perpendicular to the target surface 300 by a spacing 304.

FIG. 7 illustrates a perspective side view of a tool offset surface 306 above a sheet offset surface 302 above a target surface 300, according to an embodiment of the present disclosure. FIG. 8 shows an internal perspective view of tool offset surface 306 above sheeting offset surface 302, which is above target surface 300. Referring to fig. 1, 7 and 8, the forming control unit 102 determines a tool offset surface 306. The tool offset surface 306 is a surface that causes the operative end 112 of the forming tool 108 (e.g., a computer-generated virtual forming tool 108) to contact the sheet offset surface 302 whenever a representation of the forming tool 108 is on such tool offset surface 306, but does not extend below the sheet offset surface 302. For example, when a predetermined point of the representation of the forming tool 108 (such as a midpoint) is on the tool offset surface 306, the operative end 112 (e.g., a distal tip or point) of the forming tool 108 contacts the sheet offset surface 302 without extending below the sheet offset surface 302.

The tool offset surface 306 may be spaced from the sheet offset surface 302 a predetermined distance relative to the forming tool 108. For example, the spacing 308 between the tool offset surface 306 and the sheet offset surface 302 may be the length of the operative end 112, the distance to the center of the forming tool 108, the entire length of the forming tool 108, and the like.

Fig. 9 illustrates a perspective view of a tool offset surface 306 having a tool path 114 in accordance with an embodiment of the present disclosure. Referring to fig. 1 and 9, to determine the tool path 114, the forming control unit 102 inserts a horizontal plane 314, for example, along a Z-axis 315. The intersection of the horizontal planes 314 at each horizontal plane (level) defines a portion of the tool path 114. The forming control unit 102 may determine various levels of the tool path 114 by the maximum step down. That is, the distance between each insertion of the horizontal plane 314 along the Z-axis may be a maximum step down. In some examples, the distance between each insertion may be less than the maximum step down. As shown, tool path 114 is generated and displayed as a horizontally disposed contour on tool offset surface 306.

Referring again to fig. 1 and 8, the tool path is generally given by a set of discrete points connected by straight lines. For example, a line segment 320 between points 322 and 324 on tool offset surface 306 defines a portion of tool path 114. In at least one embodiment, the forming control unit 102 maps the line segment 320 onto the sheet offset surface 302, thereby forming a line segment 340 between points 342 and 344. The line segment 340 of the sheet offset surface 302 corresponds to the line segment 320 of the sheet offset surface 302. Points 342 and 344 correspond to points 322 and 324, respectively.

Points 342 and 344 on the sheet offset surface 302 are contact points. The contact points defined by points 342 and 344 are connected by line segment 340 to provide a complete contact path. The contact path is the path that the forming tool 108 contacts the sheet offset surface 302.

To map the tool path 114, the forming control unit 102 applies the same transformation to the points 342 and 344 applied to the target surface 300, which may be a shift perpendicular to the target surface 300. To this end, in at least one embodiment, the shaping control unit 102 modifies the target surface 300 by a vertical offset. Because the sheet offset surface 302 is also defined by vertically offsetting the target surface 300, the forming control unit 102 directly offsets the sheet offset surface 302. The forming control unit 102 may recalculate the points on the tool offset surface 306 corresponding to points 342 and 344 and connect these points by straight line segments to generate the entire tool path 114.

The forming control unit 102 may determine the tool path 114 in the same manner after or before compensating for the spring back. For example, the forming control unit 102 may generate the tool path 114 as described above with respect to fig. 5-9 after compensating for the spring back.

As described herein, embodiments of the present disclosure provide systems and methods for compensating for spring back in a progressive sheet forming process that forms a structure. Embodiments of the present disclosure provide systems and methods for elastic forward compensation during progressive sheet formation of a structure. Additionally, embodiments of the present disclosure provide systems and methods of maintaining a tool path during a progressive sheet forming process while also compensating for spring back to form a desired structural shape.

Although embodiments of the present disclosure may be described using various spatial and directional terms, such as top, bottom, lower, middle, lateral, horizontal, vertical, front, and the like, it is understood that these terms are used only with respect to the orientations shown in the drawings. The orientation may be reversed, rotated, or otherwise changed such that the upper portion is the lower portion and vice versa, horizontal becomes vertical, and the like.

As used herein, a structure, limitation, or element that is "configured to" perform a task or operation is structurally formed, configured, or adapted in particular in a manner corresponding to the task or operation. For the purposes of clarity and avoidance of doubt, an object that can only be modified to perform a task or operation is not "configured to" perform the task or operation as used herein.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of various embodiments of the disclosure should, therefore, be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled. In the appended claims and this detailed description, the terms "including" and "in which" are used as the plain-english equivalents of the respective terms "comprising" and "in … …. Furthermore, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Additionally, the limitations of the following claims are not written in a device-plus-function format, and are not intended to be interpreted based on 35u.s.c. § 112(f), unless and until such claim limitations explicitly use the phrase "device for …," followed by a functional statement without additional structure.

Additionally, the present disclosure includes embodiments according to the following clauses:

clause 1. a progressive sheet forming system (100) configured to form a structure (110) by a progressive sheet forming process, the progressive sheet forming system (100) comprising:

a forming control unit (102) that compensates for springback of the structure (110) to be formed by the progressive sheet forming process by modifying at least a portion of a tool path (114) of a forming tool (108) used to form the structure (110) based on the springback.

Clause 2. the progressive sheet forming system (100) of clause 1, wherein the forming control unit (102) determines a target shape of the structure to be formed (110) and simulates a progressive sheet forming operation related to the target shape.

Clause 3. the progressive sheet forming system (100) of clause 2, wherein the forming control unit (102) compares a difference between the target shape and a structure (110) resulting from the progressive sheet forming operation to determine one or more offsets (123) that compensate for the springback, wherein the one or more offsets (123) relate to force vectors that oppose the springback.

Clause 4. the progressive sheet forming system (100) of clause 2 or clause 3, wherein the forming control unit (102) virtually simulates the progressive sheet forming operation, while the forming tool (108) does not physically operate on the structure (110).

Clause 5. the progressive sheet forming system (100) of any of clauses 1-4, wherein the forming control unit (102) determines geometric errors (127) across the entire simulated structure (110).

Clause 6. the progressive sheet forming system (100) of clause 5, wherein the forming control unit (102) shifts (123) a point (322) on the contour (121) perpendicular to the target geometry in response to the geometric error (127) being greater than a predetermined threshold.

Clause 7. the progressive sheet forming system (100) of clause 6, wherein after the forming control unit (102) shifts (123) the point (322), the forming control unit (102) determines whether any set of consecutive contours (121) has a maximum vertical deviation (117) greater than a maximum step down (119).

Clause 8. the progressive sheet forming system (100) of clause 7, wherein in response to there being at least one set of consecutive profiles (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119), the forming control unit (102) inserts at least one compensation profile (121) between a target profile (121) and at least one profile (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119).

Clause 9. the progressive sheet forming system (100) of clause 8, wherein the forming control unit (102) further maps the compensation contour (121) onto the structure (110) to form a compensated geometric shape.

Clause 10. the progressive sheet forming system (100) according to any of clauses 1 to 9, wherein the forming control unit (102) maps a contour (121) with at least one surface (302) of the structure (110).

Clause 11. the progressive sheet forming system (100) of any of clauses 1-10, further comprising the forming tool (108), wherein the forming tool (108) is configured to follow the modified tool path (114) to form the structure (110).

Clause 12. a progressive sheet forming method configured to form a structure (110) by a progressive sheet forming process, the progressive sheet forming method comprising:

compensating, by a forming control unit (102), for springback of a structure (110) to be formed by the progressive sheet forming process, wherein the compensating comprises modifying at least a portion of a tool path (114) of a forming tool (108) used to form the structure (110) based on the springback.

Clause 13. the progressive sheet forming method of clause 12, wherein the compensating comprises:

determining a target shape of the structure (110) to be formed; and

simulating a progressive sheet forming operation associated with the target shape.

Clause 14. the progressive sheet forming method of clause 13, wherein the compensating further comprises comparing a difference between the target shape and a structure (110) resulting from the progressive sheet forming operation to determine one or more offsets (123) that compensate for the springback.

Clause 15. the progressive sheet forming method of clause 13 or clause 14, wherein the simulating comprises virtually simulating the progressive sheet forming operation without physical manipulation of the structure (110) by the forming tool (108).

Clause 16. the progressive sheet forming method of any of clauses 12-15, wherein the compensating comprises determining geometric errors (127) across the entire simulated structure (110).

Clause 17. the progressive sheet forming method of clause 16, wherein the compensating further comprises offsetting a point (322) on the contour (121) that is perpendicular to the target geometry in response to the geometric error (127) being greater than a predetermined threshold.

Clause 18. the progressive sheet forming method of clause 17, wherein the compensating further comprises determining whether any set of consecutive contours (121) after the offsetting has a maximum vertical deviation (117) greater than a maximum step down (119).

Clause 19. the progressive sheet forming method of clause 18, wherein the compensating further comprises, in response to there being at least one set of consecutive profiles (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119), inserting at least one compensation profile (121) between a target profile (121) and at least one profile (121) having a maximum vertical deviation (117) that exceeds the maximum step down (119).

Clause 20. the progressive sheet forming method of clause 19, wherein the compensating further comprises mapping the compensation contour (121) onto the structure (110) to form a compensated geometric shape.

Clause 21. the progressive sheet forming method of any of clauses 12-20, wherein the compensating comprises mapping a contour (121) with at least one surface (302) of the structure (110).

Clause 22. a progressive sheet forming system (100) configured to form a structure (110) by a progressive sheet forming process, the progressive sheet forming system (100) comprising:

a forming tool (108); and

a forming control unit (102) that compensates for the springback of the structure (110) to be formed by the progressive sheet forming process by modifying at least a portion of a tool path (114) of the forming tool (108) used to form the structure (110) based on the springback, wherein the forming control unit (102) determines a target shape of the structure (110) to be formed and simulates a progressive sheet forming operation in relation to the target shape, wherein the forming control unit (102) compares a difference between the target shape and a structure (110) resulting from the progressive sheet forming operation to determine one or more offsets (123) that compensate for the springback, wherein the one or more offsets (123) relate to force vectors that oppose the springback, wherein the forming control tool (102) maps a contour (121) with at least one surface (302) of the structure (110), and is

Wherein the forming tool (108) is configured to follow the modified tool path (114) to form the structure (110).

This written description uses examples to disclose various embodiments of the disclosure, including the best mode, and also to enable any person skilled in the art to practice various embodiments of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of various embodiments of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if the examples have structural elements that do not differ from the literal language of the claims, or if the examples include equivalent structural elements with insubstantial differences from the literal languages of the claims.